Advisory: Western Digital Caviar Green HDD Owners

[Searinox]

A rather widespread and considerably serious issue has come to my attention.

A large number of WD Caviar Green HDD models have a serious design flaw that could shorten their life. The issue is caused by a power-saving function which, due to the way it is tuned, will trigger excessively often, wearing the drive out almost a hundred times faster.

Official WD Advisory: http://wdc.custhelp.com/app/answers/.../130/p/227,294
News Article: http://news.softpedia.com/news/WD-Ca...w-196159.shtml

Short Explanation:

The disk drive's main mechanism consists of spinning platters and heads which read the platters, similar to a gramophone record. The head however, does not actually touch the disk, rather hovers above it. The Green series of WD drives were designed to save power, and thus "park" the head whenever the drive idles for more than 8 seconds. On some setups it is normal for the drives to go into idle but be polled every few tens of seconds or 1-2 minutes to read data, scan files, or log activity. This causes the head to park and unpark excessively. In many of the drive models' specifications, the rating for total number of head loads/unloads is around 300000. Due to runaway activity, this number can be reached within months or 1-2 years. Regular drives lack this "feature" altogether and hardly reach hundreds of cycles over many years, but the WD greens can reach a hundred thousand in an year.

How to tell if you're affected:

First, you need to know if you have a Caviar Green model. For Windows users, this can be found in Computer -> Properties -> Device Manager -> Disk Drives. Try googling the model or putting it under WD's website search feature.

Once you have determined that you have a WD Green model, you need to know if it is affected by the bug. Several freeware tools such as SpeedFan and HDtune are able to show drive SMART parameters. SMART is a set of self-diagnostics data of the drive reporting its own state. Look for a parameter called "Load Cycle Count". It is possible that the parameter be expressed in hex, but although the number format may confuse, one basic rule applies - a number composed of 5 or more characters should be considered unusually high and thus an indicator of the problem.

Note that more newly-produced drives of these problematic models may have an updated firmware with the bug fixed and therefor behave normally.

Solution:

WD has provided a tool to mitigate the problem called wdidle3. It is a command-line executable and is capable of changing the drive's idle wait timer or even disable it. The tool however, can only be run in DOS mode and thus requires a bootable DOS drive. Many freeware DOS systems exist ready to download and burn to an optical disc or USB drive.

WARNING: This is an advanced tool whose misuse could result in a non-functional "bricked" harddrive and loss of all data on it. The tool INDISCRIMINATELY applies these settings to ALL WD drives it can find that allow idle3 timers to be adjusted, so if you have more than 1 WD drive it is recommended to physically disconnect their power/data cable before using the tool. Advanced IT skills are highly recommended as this procedure is done solely at your own risk/responsibility.

The tool WILL work on all affected models despite the page stating only a handful of models.

Tool: http://support.wdc.com/product/downl...id=609&sid=113

Once booted into the environment, run wdidle3 /s300 to set the idle timer to 300 seconds(5 minutes), the maximum allowed. Wdidle3 /d will disable the timer altogether BUT may not work on all models(did not work on my WD6400AARS). The only way to check if it did is to boot back into the OS and check the SMART parameters on your own to see if the number keeps going up as quickly.

While 5 minutes may solve the vast majority of cases, it may not be slow enough(as in my case). If disabling isn't supported either, a simple solution, for Windows users, is to download a program like SpeedFan and let it run in the background. It uses very little CPU and memory, and keeps polling the drives every 1 minute, thus never reaching the 5-minute timer and effectively never parking the head except on power off or sleep. The disk activity they cause is nigh inexistent and shouldn't impact performance. DO NOT USE such a tool if you haven't already increased the timer to 5 minutes as it will have the opposite effect!

Personal Account:

I bought a WD Caviar Green 640GB model WD6400AARS 9 months ago, last winter. 2 days ago I decided to check my drive SMART parameters out of boredom and SpeedFan offers an option to check these values in-depth online. I saw 116 thousand load cycles and a warning that the number is too high.

A simple googling of the issue revealed this very well known highly talked about problem with WD Green drives, including a long-running thread on their own forums.

I went ahead and downloaded a premade boot image with the tool and burnt it to the DVD then rebooted in that mode. My experience was slightly scary as everytime I finished running the tool DOS froze up. But if froze up WHILE reloading the "norton commander"-like browser, AFTER finishing the tool execution so at least I knew the program was completing with success.

I had a 320GB WD drive alongside the Green and another 2 drives on IDE, one of them being a Maxtor. The tool ignored the IDE drives but forced changes on both the 320 and 640 drive. I do mention the 320 had the timer disabled by default. wdidle3 /r will show the state of the drives. However, disabling the timer did not help in my case and I had another 200 parks over the next half an hour.

I went back and instead set the timer to 300, which as I said applied to BOTH drives. Back in Windows the numbers finally stopped going up as fast but I still saw them increasing at an average of 6-7 an hour. World of Warcraft is on the Green and while I'm in it the number does not go up as the activity prevents the drive from idling. However I crunched the numbers on an year of activity and found 50-60 thousand parks an year to be unacceptable. The data on the website is also confusing. My drive's model is specced for 300000 cycles but the bug advisory states it should go up to 1 million without issues.

Finally I downloaded SpeedFan and left it running in the background. Its once-a-minute polling of SMART attributes put a complete stop to the increasing cycle count, which should now only go up by 1 per startup. SpeedFan is a quiet nice little program but I think others can do the job too, perhaps even tasks programmed into Task Scheduler or defrag-on-idle or indexing services. I do not know about other OSs. I have no clue how my 320GB drive was affected since it doesn't count head parks. I recommend physically disconnecting any other WD drives before using this tool as it indiscriminately applies settings to all configurable drives.

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Since my drive is 9 months old and has already used up more than a third of its load cycle lifespan, I thought this info mandatory to share with the rest of you.

[Autumn Wind]

I am all for ways to save energy and such though I hear bad things about the WD Caviar Greens. Now on the other hand, I hear great things about both the Scorpio and Caviar Blacks.